1. Field of the Invention
The present invention relates to an artificial stone composition and a method of manufacturing an artificial stone. More particularly, the present invention relates to a method of manufacturing an artificial stone, light in weight and higher in hardness, strength and density, which has an excellent surface condition like granite or marble and has excellent properties such as surface hardness and surface wear resistance, and provides an artificial stone useful as a material for a wall, a floor and other building materials, civil engineering materials and a stone column.
2. Description of the Related Art
There is known a conventional practice of manufacturing an artificial stone to crush a material stone into appropriate pieces, mix calcium carbonate and a resin, and then hardening the same. More specifically, Japanese Provisional Patent Publication No. S61-101,443 discloses a method of obtaining a lumpy artificial stone capable of withstanding cutting, which comprises the steps of mixing material stone powder and resins in vacuum, injecting the mixture into a mold, taking out the molded mixture and subjecting the same to cutting.
Another Japanese Patent Publication No. S53-24,447 discloses, for the manufacture of an artificial stone by the use of powder particles of a natural stone and a synthetic resin, the use of the raw materials at a prescribed mixing ratio, and the necessity of applying a sufficient pressure after placing the raw materials in a mold.
However, artificial stones obtained by these conventional methods pose a problem that, in spite of the use of powder particles of natural stones, the color tone or the feeling of depth is not always satisfactory.
Conventional artificial stones are defective in that the color tone of the surface inevitably becomes darkish and dull. It is therefore conventionally an actual state that it is very difficult to achieve a granite-like or marble-like surface provided with a feeling of transparency, deepness and massiveness.
A conceivable reason is that surface light reflection and absorption largely differ between artificial stones, depending upon the chemical composition, the particle size and blending ratio of natural stone powder particles, and almost no study has conventionally been made on such point of view.
Further, the chemical composition of an artificial stone largely affects moldability, and depending upon the size or blending ratio of natural stone powder particles blended in an artificial stone, or the ratio of a binder resin, a problem may be encountered in that fluidity for molding is lost, or bubbles remain in the molded body, thus seriously impairing quality and strength of the product artificial stone.
To overcome these problems, Japanese Patent Publication No. S53-24,447 proposes fluidization through increase in the amount of resins, which permits prevention of generation of bubbles.
However, on the other hand, while increasing the resin content is useful for ensuring a satisfactory fluidity and preventing production of bubbles, this exerts an adverse effect on properties of a resulting artificial stone.
More specifically, use of a large quantity of resins leads to resinification of an artificial stone product, and the resultant product means only the presence of natural stone powder particles in resins, and physical properties thereof are closer to those of the raw material resins than to those of the raw material stone. In spite of the name of an artificial stone, it is only a resin product having an appearance of a stone.
Under these circumstances, there has been a demand for development of a novel artificial stone which solves the defects of the conventional artificial stones, and when using powder particles of natural stones and the like as raw materials, has a dense structure, gives a feeling of deepness, together with a transparent color tone, has features of a natural stone such as granite or marble, and is excellent in moldability, permitting achievement of any arbitrary shape such as a plate or a rod.